Answers are grounded in this paper and cite their sources.
The construction of a modified Hartley oscillator transmitter activated through a pressure switch is described. When this device is placed within the rumen of a cow which is allowed unrestricted movement in the pasture, frequency-modulation signals are transmitted to a recording receiver whenever a preselected pressure is exceeded. The pressure at which transmission begins is determined by the capacitance across the coil of the circuit.
No takes yet. Share an insight, caveat, or question.
Loyal C. Payne (1960) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: